export default {
  bind(el, binding, vnode, oldVnode) {
    //弹框可拉伸最小宽高
    let minWidth = 400
    let minHeight = 300
    //初始非全屏
    let isFullScreen = false
    //当前宽高
    let nowWidth = 0
    let nowHeight = 0
    //当前顶部高度
    let nowMarginTop = 0
    //获取弹框头部（这部分可双击全屏）
    const dialogHeaderEl = el.querySelector('.el-dialog__header')
    let hasSetBodyHeight = false
    //弹窗
    const dragDom = el.querySelector('.el-dialog')
    //给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog
    // dragDom.style.overflow = 'auto'
    //清除选择头部文字效果
    dialogHeaderEl.onselectstart = new Function('return false')
    //头部加上可拖动cursor
    dialogHeaderEl.style.cursor = 'move'

    // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
    const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null)

    //头部插入最大化最小化元素
    let maxMin = document.createElement('button')
    maxMin.className += ' el-dialog__headerbtn el-dialog__minmax'
    maxMin.style.right = '40px'
    maxMin.style.color = 'black'
    maxMin.title='最大化'
    maxMin.innerHTML = '<i class="el-icon-full-screen" onMouseOver="this.style.color=\'white\'" onMouseOut="this.style.color=\'inherit\'"></i>'
    dialogHeaderEl.insertBefore(maxMin,dialogHeaderEl.childNodes[1])

    let moveDown = (e) => {
      // 鼠标按下，计算当前元素距离可视区的距离
      const disX = e.clientX - dialogHeaderEl.offsetLeft
      const disY = e.clientY - dialogHeaderEl.offsetTop

      // 获取到的值带px 正则匹配替换
      let styL, styT

      // 注意在ie中 第一次获取到的值为组件自带50% 移动之后赋值为px
      if (sty.left.includes('%')) {
        styL = +document.body.clientWidth * (+sty.left.replace(/\%/g, '') / 100)
        styT = +document.body.clientHeight * (+sty.top.replace(/\%/g, '') / 100)
      } else {
        styL = +sty.left.replace(/\px/g, '')
        styT = +sty.top.replace(/\px/g, '')
      }

      document.onmousemove = function (e) {
        // 通过事件委托，计算移动的距离
        const l = e.clientX - disX
        const t = e.clientY - disY

        // 移动当前元素
        dragDom.style.left = `${l + styL}px`
        dragDom.style.top = `${t + styT}px`

        //将此时的位置传出去
        //binding.value({x:e.pageX,y:e.pageY})
      }

      document.onmouseup = function (e) {
        document.onmousemove = null;
        document.onmouseup = null;
      }
    }

    dialogHeaderEl.onmousedown = moveDown
    let bodyHeight = 'auto'

    function setMaxMin() {
      if (isFullScreen === false) {
        let i = maxMin.querySelector('.el-icon-full-screen')
        i.classList.remove('el-icon-full-screen')
        i.classList.add('el-icon-crop')
        maxMin.title = '还原'
        bodyHeight = dragDom.querySelector('.el-dialog__body').offsetHeight + 'px'
        nowHeight = dragDom.clientHeight
        nowWidth = dragDom.clientWidth
        nowMarginTop = dragDom.style.marginTop
        dragDom.style.left = 0
        dragDom.style.top = 0
        dragDom.style.height = '100VH'
        dragDom.style.width = '100VW'
        dragDom.style.marginTop = 0
        isFullScreen = true
        dialogHeaderEl.style.cursor = 'initial'
        dialogHeaderEl.onmousedown = null
        dragDom.classList.add('is-fullscreen')
        if(!hasSetBodyHeight) {
          dragDom.querySelector('.el-dialog__body').style.height = (nowHeight + 50) +'px'
          hasSetBodyHeight = true
        }
      } else {
        let i = maxMin.querySelector('.el-icon-crop')
        i.classList.remove('el-icon-crop')
        i.classList.add('el-icon-full-screen')
        maxMin.innerHTML = '<i class="el-icon-full-screen"></i>'
        maxMin.title = '最大化'
        dragDom.style.height = 'auto'
        dragDom.style.width = nowWidth + 'px'
        dragDom.style.marginTop = nowMarginTop
        isFullScreen = false
        dialogHeaderEl.style.cursor = 'move'
        dialogHeaderEl.onmousedown = moveDown
        dragDom.classList.remove('is-fullscreen')
        dragDom.querySelector('.el-dialog__body').style.height = bodyHeight
        hasSetBodyHeight = false
      }
    }
    //点击放大缩小效果
    maxMin.onclick = setMaxMin
    //双击头部效果
    dialogHeaderEl.ondblclick = setMaxMin

    //拉伸
    let resizeEl=document.createElement('div')
    dragDom.appendChild(resizeEl)
    //在弹窗右下角加上一个10-10px的控制块
    resizeEl.style.cursor = 'se-resize'
    resizeEl.style.position = 'absolute'
    resizeEl.style.height = '10px'
    resizeEl.style.width = '10px'
    resizeEl.style.right = '0px'
    resizeEl.style.bottom = '0px'
    //鼠标拉伸弹窗
    resizeEl.onmousedown = (e) => {
      // 记录初始x位置
      const clientX = e.clientX
      // 鼠标按下，计算当前元素距离可视区的距离
      const disX = e.clientX - resizeEl.offsetLeft
      const disY = e.clientY - resizeEl.offsetTop
      document.onmousemove = function (e) {
        // 移动时禁用默认事件
        e.preventDefault()
        // 通过事件委托，计算移动的距离
        const x = e.clientX - disX + (e.clientX - clientX)
        const y = e.clientY - disY
        //比较是否小于最小宽高
        dragDom.style.width = x > minWidth ? `${x}px` : minWidth + 'px'
        dragDom.style.height = y > minHeight ? `${y}px` : minHeight + 'px'
        if(!hasSetBodyHeight) {
          dragDom.querySelector('.el-dialog__body').style.height = 'calc(100% - '+dialogHeaderEl.offsetHeight+'px)'
          hasSetBodyHeight = true
        }
      }
      //拉伸结束
      document.onmouseup = function (e) {
        document.onmousemove = null
        document.onmouseup = null
      }
    }
  }
}
